How much of that KCl infusion remains in the extracellular compartment? Not much, but more than I expected.
70 kg * 60% water = 42 liters Total body water
one third of total body water is extracellular = 0.33*42 = 14 liters
14 * 3 mEq/L of K in our hypokalemic dude gives extracellular K of 42 mEq
His potassium goes up to 3.4 mEq/L as we know (clinmedjournals.org/articles/jcnrc…)
new extracellular K is 3.4 * 14 or 47.6 mEq of potassium